Merge #16207: test: stop generating lcov coverage when functional tests fail

9218ce8 Failing functional tests stop lcov (Aseem Sood)

Pull request description:

  Fixes #15648

  Functional tests can fail and lcov still generates a coverage file, which is inaccurate. This change stops `make` from proceeding if functional tests fail.

  before:

  ![image](https://user-images.githubusercontent.com/6106941/59449220-a9a11480-8dd4-11e9-9eff-81c42513aafa.png)

  after:
  ![image](https://user-images.githubusercontent.com/6106941/59449234-b160b900-8dd4-11e9-9d80-6e9c7f41c241.png)

ACKs for commit 9218ce:
  laanwj:
    straightforward enough ACK 9218ce8

Tree-SHA512: 6bbba625f021471d897e911b0df7703153634ef133e295e7be8639346e11f5532bac04e9bab7d793e520fdf4b903219cacecc2ce1e25da0a6828a34a396729e2

Author: MarcoFalke

Makefile.am

@@ -198,7 +198,7 @@ test_bitcoin_filtered.info: test_bitcoin.info
 	$(LCOV) -a $@ $(LCOV_OPTS) -o $@
 
 functional_test.info: test_bitcoin_filtered.info
-	-@TIMEOUT=15 test/functional/test_runner.py $(EXTENDED_FUNCTIONAL_TESTS)
+	@TIMEOUT=15 test/functional/test_runner.py $(EXTENDED_FUNCTIONAL_TESTS)
 	$(LCOV) -c $(LCOV_OPTS) -d $(abs_builddir)/src --t functional-tests -o $@
 	$(LCOV) -z $(LCOV_OPTS) -d $(abs_builddir)/src